Stage 1 is preattachment, which occurs between birth and 6–8 weeks. Babies learn to recognize their caregivers by smell and sound, and engage in behaviors that elicit caretaking from adults. The interaction between child and caregiver begins to become established.
Stage 2 is Attachment in the making, which occurs between 6–8 weeks and 6–8 months. Babies smile and laugh with the caregiver, and rely on that person when they are upset. They are beginning to identify this individual as the person to be counted upon.
Stage 3 is True attachment, which occurs between 6–8 and 18 months. An attachment figure has been singled out (usually the mother), and is the base of socioemotional comfort. Separation from this figure results in distress.
Stage 4 is Reciprocal relationships, which occurs from 18 months on. Developing cognitive and language skills allow for more interaction in the attachment relationship, initiative in actions, and understanding of others' feelings and goals.